(1) Field of the Invention
This invention relates to extrusion presses, and more particularly to die transfer mechanisms on extrusion presses.
(2) Description of Prior Art
An extrusion press is utilized to force a heated metal slug or billet through a shaped orifice called a die stack. The die stack is mounted in a carrier which may in turn be supported on a horizontal track or gibs fixed to a massive vertically arranged platen. The die is aligned with a passageway or egress hole in the plate or platen which provides reinforcement thereagainst, while permitting the metal to be forced and extruded therethrough. It is necessary to change the die from time to time to permit changes in the extrusion pattern, or to replace a worn die. Several methods have been proposed in the art and are shown in U.S. Pat. Nos. 2,858,017 to Kent et al; and 3,653,247; 3,844,151 and 4,103,529 to Huertigen. The patent to Kent et al, discloses a die shifter having a first cylinder mounted on the side of the platen adjacent and connected to a die slide assembly, with a second cylinder attached to the platen with a rod which pulls on the bottom of the die slide assembly. Both the first and second cylinders are used to shear the extruded article, whereupon the second cylinder is used to shift the slide slightly from in front of the orifice in the platen to enable an operator to lift the die out through the top of the slide using a crane or the like, and replacing it similarly. The '247 patent to Huertigen shows a die slide with empowering means therefor extending distantly off one side of the press. The '151 patent to Huertigen shows a die slide arrangement using a chain and sprockets adapted to move a die in conjunction with hydraulic unit, to a transfer station. This type of die shifting mechanism is susceptible to contamination from metal particles and necessitates constant cleaning and maintenance of the hydraulic unit components.
It is an object of the present invention to provide a die slide assembly which is compact and unobtrusive.
It is a further object of the present invention to provide a die slide assembly which does not require constant cleaning and maintenance as would some of the prior art.